Vulnerability of giant South American turtle (Podocnemis expansa) nesting habitat to climate-change-induced alterations to fluvial cycles

A change in seasonal flooding cycles in the Amazon may negatively impact nesting success of the Giant South American Turtle (Podocnemis expansa). Our aim was to devise a technique that could be replicated in the entire Amazon basin, for monitoring alterations in fluvial cycles and their effects on turtle nest mortality. We mapped the spatial distribution and height of P. expansa nests and tested the effects of different inundation scenarios within the Trombetas River Biological Reserve, Para state, Brazil. We also used historical data on water level and hatchling production to test whether the sharp decline in the Trombetas River P. expansa population over the past thirty years was related to detected changes in the flood pulse. Our models indicate that an increase of 1.5m in the water level is sufficient to decrease the time of exposure to less than the minimum required for incubation and hatching (55 days above the water) in 50% of the nesting area. This model explains the low hatchling production in dry seasons when the total nesting site exposure was less than 200 days. Since 1971, there was an average decline of 15 days per decade in sandbank exposure during the nesting season (a total of 62 days from 1971 to 2015). However, the decrease in sandbank exposure was not significantly correlated with the sharp decline in hatchling production. Changes to the water cycle in combination with the main sources of decline (overharvest, construction of dams, and dredging of riverbeds) might have an accumulative effect on P. expansa populations. © The Author(s) 2016

Home range, movements and habitat selection of the freshwater turtle Hydromedusa maximiliani (Testudines: Chelidae) at the Parque Estadual Carlos Botelho, São Paulo state, Brazil

Um fator-chave para a conservação da biodiversidade é a adequada estruturação de áreas protegidas. Para quelônios, no entanto, a determinação do tamanho e da configuração dessas áreas requer a execução de estudos de longa duração capazes de integrar as diversas informações que garantam o sucesso reprodutivo, o recrutamento de novos indivíduos e o entendimento de todos os aspectos necessários para o extenso ciclo de vida, assegurando, portanto, diversidade genética que proporcione a persistência das populações desses animais ao longo do tempo. Um total de dezenove cágados adultos (10 machos e nove fêmeas) foram equipados com rádio-transmissores e outros 18 animais (11 fêmeas e sete machos) foram monitorados com bobinas de rastreamento com a finalidade de determinar a área de vida, os padrões de movimentação e o uso e seleção de habitat de Hydromedusa maximiliani, uma espécie de cágado Vulnerável e endêmica de áreas de Mata Atlântica, um dos ecossistemas mais ameaçados do planeta. Por meio de diferentes estimadores (Polígono Convexo Mínimo ou MCP \"Minimum Convex Polygon\", Kernel e Cluster para os dados de telemetria) foi possível observar que H. maximiliani apresenta área de vida que varia entre 0,2 e 1,5 ha ao longo de um período anual, com média de 0,4 ha, independentemente da estação do ano. Apesar da diferença de tempo empregado no monitoramento pelos dois métodos (72 horas para o bobinas de rastreamento e 15 meses para a telemetria), observou-se que o tamanho da área de vida não foi diferente quando comparadas as estimativas obtidas. Esse resultado, bem como o baixo deslocamento apresentado pela espécie (3 a 138 m/dia) e o intenso uso de refúgios pelos indivíduos monitorados, pode ser explicado pelo comportamento sedentário e intensa fidelidade ao ambiente aquático. Contudo, esse aspecto não descarta a sua relação com o ambiente terrestre, o que, entretando, necessita de melhor e mais prolongada investigação, uma vez que a seleção de locais para a postura dos ovos é um comportamento maternal sujeito à seleção natural e que contribui para a sobrevivência e a variação fenotípica da prole.A key factor in conservation biology is a suitable design of protected areas. Long-term study is required when determining the size, structure, shape of these areas for freshwater turtles, thereby integrating essential information to guarantee the reproductive success, recruitment of new individuals into the population and persistence of the population over the years. Nineteen adult animals (10 males and 9 females) were fitted with radio-transmitters in order to analyze the home range, movement patterns, habitat use and selection of the vulnerable freshwater Hydromedusa maximiliani, an endemic and vulnerable freshwater turtle from Atlantic Rainforest in Brazil, one of the world\'s most threatened ecosystems. Another eighteen adult animals (11 females and 7 males) were also monitored with the technique of thread-bobbins. Three different methods such as MCP \"Minimum Convex Polygon\", Kernel and Cluster were applied to measure home range size which varied between 0.2 to 1.5 ha throughout a year period of monitoring, with mean size of 0.4 ha either for the wet or the dry season. No difference was found when the home range measured using different methods were compared even with the time difference between them (72 hours for thread-bobbins and 1 year for telemetry). This result associated with the low movements showed by Hydromedusa maximiliani (3 to 138 m/day) and the intense use of burrows can be explained by the sedentary behavior and intense site fidelity of the turtles with the river. Nevertheless, the importance of the terrestrial habitat for freshwater turtles is already known though longterm monitoring is necessary to study this aspect which would contribute to future conservation strategies including nests sites and also habitat use and selection of young turtles

Reproduction ecology and population viability analysis of the neotropical freshwater turtle Hydromedusa maximiliani (Testudines, Chelidae) at the Parque Estadual Carlos Botelho, São Paulo, Brazil

Com o objetivo de obter dados relacionados às estratégias reprodutivas de Hydromedusa maximiliani no Parque Estadual Carlos Botelho, SP, fêmeas e jovens foram radiografados entre setembro de 2007 e dezembro de 2008. A estação reprodutiva estendeu-se de setembro a dezembro, com a ocorrência de desovas entre novembro e dezembro, tanto em 2007 como em 2008. Das 33 fêmeas radiografadas, 19 (58%) apresentaram ovos, e, dessas, apenas três (16%) reproduziram-se nos dois anos. O tamanho da ninhada variou entre 1 e 3 ovos, mas a maioria das fêmeas (90%) apresentou dois ovos. O volume da ninhada foi de 22128,01 ± 4939,8 mm³ (10493,422136,12 mm³; N = 44). Houve fortes relações positivas entre o tamanho corpóreo das fêmeas com o tamanho dos ovos e volume da ninhada. Os dados reprodutivos obtidos no presente estudo, em conjunto com os dados populacionais estabelecidos para H. maximiliani na mesma área de estudo por outros autores, permitiram a realização de uma análise de viabilidade da população. As simulações geradas no programa VORTEX (versão 9.92) foram baseadas em dois cenários principais, denominados População Real (PR) e População Hipotética Isolada (PHI). O primeiro foi criado com base nas informações existentes para H. maximiliani, coletadas ao longo de mais de 10 anos, a partir do qual foram feitas alterações de algumas variáveis (aumento de 10% na taxa de mortalidade; aumento em duas vezes no valor de frequência de catástrofes; inclusão de depressão por endogamia com aumento de 10% no valor default do programa e diminuição da capacidade de suporte), gerando o cenário PHI, com o objetivo de avaliar as diferenças entre uma população protegida em uma unidade de conservação e uma população isolada e sujeita a maiores influências negativas. Os resultados das simulações demonstraram existir diferença significativa (p = 0,0005) entre os dois cenários com probabilidade de extinção equivalente a 31% para o cenário real e 90% para o cenário hipotético. Testes de sensibilidade foram realizados com a finalidade de verificar a influência de variações na taxa de mortalidade, catástrofes e depressão por endogamia, e forneceram indicações de que variações em todos os parâmetros testados possuem forte influência na sobrevivência da população. Estudos de longaduração e informações a respeito das espécies de áreas sujeitas a fortes pressões antrópicas, como a Mata Atlântica, são de grande importância para a conservação, já que podem auxiliar na elaboração de análises de viabilidade populacional e no delineamento de estratégias de manejo focadas nos fatores reais que ameaçam as populações.The reproductive strategies of Hydromedusa maximiliani at the Carlos Botelho State Park, SP, was verified by X-ray in females and juveniles between September 2007 and December 2008. Throughout the study two reproductive seasons were detected, both beginning in September. From a total of 33 X-rayed females, only 19 showed eggs, and three of them showed eggs in the two reproductive seasons. Clutch size varied from 1 to 3 eggs, but only one female presented one egg and another female presented three eggs. Clutch volume was 22128.01 ± 4939.8 mm³ (10493.422136.12 mm³; N = 44). Female body size was positively correlated to clutch volume, a pattern usually detected in chelonians. Reproductive information acquired in the present study together with population data available for H. maximiliani in the study site makes it possible a population viability analysis using the software VORTEX (version 9.92). A principal scenario (Real Population) was created based on life-history data collected throughout 10 years. In order to compare the protected area with an unprotected hypothetical area regarding the persistence of the population, this scenario was modified by altering some variables (10% increasing of mortality rate, 10% increasing of inbreeding depression, decreasing of carrying capacity), which generates a scenario named Hypothetical Isolated Population. Results were compared and sensitivity tests were carried out to verify the influence of variation in mortality ratio, catastrophes and inbreeding depression. There was a significant difference between the two scenarios (p = 0.0005). The extinction risk was 31% for Real Population and 90% for Hypothetical Isolated Population. The sensitivity analysis indicated that mortality ratio, deforestation, forest fires and inbreeding depression strongly influence the population survival. Long-term studies and biological information on species inhabiting areas subjected to anthropogenic impacts, like the Atlantic Rainforest, are vital to conservation actions, since they make it possible population viability analyses and the design of management strategies to threatened populations

Home Range of Yellow-Spotted Amazon River Turtles (Podocnemis unifilis) (Testudines: Podocnemididae) in the Trombetas River Biological Reserve, Pará, Brazil

Adult Podocnemis unifilis were monitored using VHF radio tracking from September 2013 to September 2014 in the Rio Trombetas Biological Reserve, Pará, Brazil. Our aim was to analyze the use of space by this species near the nesting beach base by describing size and overlap of estimated home ranges. Transmitters were attached to 10 males and 10 females. The mean home range size calculated through the fixed-kernel (FK) method with 95% of the fixes was 79.28 ± 77.08 ha (0.56-215.07 ha; n = 13). The mean of overlapping areas was 14% with FK95% (0.02%-81%; n = 13) and 5% with FK50% (0.1%-23%; n = 9). There was a significant difference in the mean overlapping areas between females and males. The analysis of the overlap of activity centers estimated by FK50% is extremely important for the establishment of conservation strategies in the management plan for this species in the reserve. We were able to identify 2 critical areas for the maintenance of this population where there was a frequent overlap of activity centers: the first, identified during the dry season, was composed of small overlaps among 7 turtles and was near the nesting areas on the clay banks within the Lago Jacaré; the second, identified during the rainy season, was composed of a concentration of overlap areas of larger size among 6 turtles and was an open area in the flooded forest. It is important not only to protect the nesting areas during the dry season but also to protect flooded forest areas with the major intensity of use along with the canals that link the flooded forests to the lakes in the rainy season. For conservation purposes, it is necessary to continue the protection of the nesting beaches throughout the savannas inside the lake where the species nests in the dry season. The flooded forest areas that are zones of intense use during the rainy season, and the canals where the turtles can move between lakes must be protected throughout the year. © 2019 Chelonian Research Foundation

Structure of a Population of Hydromedusa maximiliani (Testudines, Chelidae) from Parque Estadual da Serra do Mar, an Atlantic Rainforest Preserve in Southeastern Brazil

We studied the structure of a population of Hydromedusa maximiliani associated with a stream in Parque Estadual da Serra do Mar, Nucleo Itutinga-Piloes, southeastern Brazil, between October 2004 and October 2005. Twenty-five individuals were captured, and a population size of 43.72 +/- 23.7 individuals was estimated. This value is similar to that of the population of Parque Estadual Carlos Botelho, another Atlantic forest reserve of southeastern Brazil. Males were recaptured more frequently than females, suggesting higher activity and/or greater movement of males.Concessionaria Ecovias dos Imigrantes and Universidade Metodista de Sao Paul

Anuran fauna of the Parque Estadual Carlos Botelho - Nficleo Sete Barras, southeastern Brazil: species composition, use of breeding sites, and seasonal patterns of breeding activity

The goal of this work was to study the species composition, the use of breeding sites, and the seasonal patterns of breeding activity of the anuran fauna from Parque Estadual Carlos Botelho - Nucleo Sete Barras, state of Sao Paulo, southeastern Brazil. Fieldwork was carried out from September 2005 to October 2007 through two main methods: active visual search inside a 10 ha- permanent plot and aural and visual search in seven previously selected aquatic breeding habitats. Species richness was related to the sampling effort by means of species accumulation curve and through non-parametric estimators. Thirty-three species distributed in 12 families were recorded, from which 69% are endemic to the Atlantic Forest. Trachycephalus mesophaeus represents a new record for the park. Cycloramphus lutzorum is included as Data Deficient in the IUCN list. The species accumulation curve did not stabilize, showing some tendency to rise. The use of breeding sites by 20 species was compared using cluster analysis, which revealed two major groups: the first with five species (two habitat generalists and three stream specialists) and the second composed by the other species (with different reproductive modes associated with flooded environments). The breeding period of most species was associated to the rainy season (October to February), and only Scinax hayii showed continuous breeding activity during the entire period of study.Funding Agencies|FAPESPFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [04/15938-5, 99/09635-0]</p